[Qemu-devel] [PULL 1/5] display: virtio-gpu-3d: check virgl capabilities max_size

[Gerd Hoffmann <kraxel@redhat.com>]

From: Prasad J Pandit <pjp@fedoraproject.org>

Virtio GPU device while processing 'VIRTIO_GPU_CMD_GET_CAPSET'
command, retrieves the maximum capabilities size to fill in the
response object. It continues to fill in capabilities even if
retrieved 'max_size' is zero(0), thus resulting in OOB access.
Add check to avoid it.

Reported-by: Zhenhao Hong <zhenhaohong@gmail.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-id: 20161214070156.23368-1-ppandit@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/display/virtio-gpu-3d.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/display/virtio-gpu-3d.c b/hw/display/virtio-gpu-3d.c
index 23f39de..e29f099 100644
--- a/hw/display/virtio-gpu-3d.c
+++ b/hw/display/virtio-gpu-3d.c
@@ -371,8 +371,12 @@ static void virgl_cmd_get_capset(VirtIOGPU *g,
 
     virgl_renderer_get_cap_set(gc.capset_id, &max_ver,
                                &max_size);
+    if (!max_size) {
+        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER;
+        return;
+    }
+
     resp = g_malloc(sizeof(*resp) + max_size);
-
     resp->hdr.type = VIRTIO_GPU_RESP_OK_CAPSET;
     virgl_renderer_fill_caps(gc.capset_id,
                              gc.capset_version,
-- 
1.8.3.1